Will make it easier to comprehend that the bullet update function is
actually correct with regards to only looking at a single variable.
(Yes, I know, hard to believe!)
Part of P0149, funded by Blue Bolt, Ember2528, and -Tom-.
Adding op/, main/, and end/ directories does nicely cover a great
majority of the "not really further classifiable slices" implied in
d56bd45.
Part of P0086, funded by [Anonymous] and Blue Bolt.